Filament tensioner



June 30, 1953 J, o, REECE ETAL 2,643,857

-- FILAMENT TENSIONER Filed Aug. 30, 1950 Fig.1.

llllllip iii iNVENTORfi. Jam: Ouvm R5505.

Patented June 30, .1953

FILAMENT TENSIONER John Oliver Reece and Stanley- Reece Wandsworth, L n on. Englauiigl 'Appli'cation August 30, 1950, serial N6. 182 304 I In Great Britain August 30, 1949 :v

This invention relates to tension regulation in stressed wire and the like, and more especially to such as are used in the tying of packages by means of wires or straps surrounding such package. It also relates to the securing of packages or packs to bases on which they are to be carried as, for example, for transport purposes.

It is customary to secure goods in the form of bales of packages by passing around them wires or metal straps (hereinafter referred to under the general term wire) bringing the ends together and securing the ends to one another by the use of a tool by means of which tension may be given to the wire prior to the fastening of the ends together.

Owing to the variable compressibility of the package or of the goods therein and the liability to swelling or shrinkage during the vicissitudes of transport and danger of excessive stress from rough handling or other cause, it is necessary that the tension given to the wire should not be such as to exceed the capacity of the wire to resist breaking strain on the wire or the strain that the wire is likely to be called upon to withstand in the course of transport or storage.

Since the strain on the wire is a function of the force exerted, whether mechanically or manually in the operation of the tool and there is nothing except his experience to guide a manual operator in applying such force as he may .exert without danger of breaking the wire in the process, or of exerting a stress exceeding that which the wire may safely bear, breakages of wire are not infrequent, especially where the muscular strength of the operator is above the normal.

The purpose of the present invention is to provide means whereby the stress applied by the operator cannot exceed a definite predetermined value.

A further purpose is to provide that on the attainment of such predetermined value any further increase of the operating force shall not result in any increase of the tension on the wire, but will result in the maintenance of the tension then reached. This situation occurs practically instantaneously on the attainment of the said predetermined value.

With these objects in view this invention consists in the provision between the operators tensioning tool and the holding tool for the wire ends of an automatically operative releasing clutch, of which the one part is adapted to be rotated by the operators tensioning tool and the other part rotates the wire ends holding tool.

2 Claims'. (01. 254-5161) The-tire nartsof; this c ut h are. held on against the othe by a; spring-havin means for applyingt ision thereto and. consequent y per:

mitting the clutch to yield when the tensioning stress on the wire reaches the value at which the clutch is set to yield.

Such a clutch may therefore be regarded as a tension regulator.

Fig. 1 is a central vertical section and Fig. 2 is an elevation of part of the clutch.

A represents that part of the clutch which is so mounted as to be operated by the tension "applying means, here shown as provided with ratchet teeth engaged by a dog carried by the tension applying lever.

B represents that part of the clutch which receives the wire. ends and operates to engage the wire ends and twist or seam them together andthussecure the wire from slipping back.

C represents the interposed spring which holds the clutch members in engagement with one another until the-applied tensioning force exceeds the stress which the wire is intended to withstand.

The clutch parts or abutments A and B are mounted concentrically on the cylindrical part a of a central stem and are retained thereon by a head I) at one end and a nut c at the other end, the length of the stem between the head 1;.

and nut 0 being such as to permit of the two clutch parts A and B moving apart sufficiently to freely clear one another.

The spring 0 is of a comparatively stiff'short helical type and when in position and unstressed tends to hold the clutch parts A and B together in contact.

The clutch is preferably of that type in which the one member has in its facerecesses to hold steel balls projecting beyond its face and the other member has corresponding sockets into which the balls engage. In order that the two parts of the clutch may disengage it is necessary that they be allowed suflicient play to permit the balls to disengage from the sockets. This movement however causes the spring C to be compressed and the stress set up in the spring C by such compression acts as a limit to the eifective tension that can be exerted by the operator or operating tool on the wire.

What we claim as our invention and desire to secure by Letters Patent of the United States is:

1. A filament tensioning device comprising a rotary annular element having at least one end open and adapted to receive and hold one end of the filament, a spindle carrying said element rotatably thereon, the end of the spindle being each ball being partly engaged in a recess of one.

abutment and partly engaged in a recess of the other abutment, a spring surrounding said spin dle which urges said abutments towards each other, means on said spindle to transmit the force of said spring to said second annular abutment and a spring adjustment means including a portion located within the annular element and readily accessible at said open end of said element for adjustment whereby when the second abutment is rotated it will drive the said element until the tension on the filament reaches a predetermined limiting value according to the'set ting'of the adjustment member whereupon the abutments separate against the action of the spring and ride over the balls.

2. A device as claimed in claim 1 wherein the said element is cup shaped and has slots on .one end to receive the filament, and the spring adjusting means includes a slotted head on one end of the spindle which latter isthreaded at its other end, saidfispring being a helical spring which surrounds the spindle and is located. in

said element between said head and the bottom of the cup.

JOHN OLIVER RE'ECE. STANLEY HENRY References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 820,194 Hofiman May 8, 1906 1,840,682 Sheldrick et a1 Jan. 12, 1932 2,146,104 Adamson Febfll, 1939 2,204,572 Childress June 18, 1940 Embree Apr. 29, 1952 

